Role of ionic liquids in organic-inorganic metal halide perovskite solar cells efficiency and stability

Organic-inorganic metal halide perovskite solar cells (PSCs) are developing in a rapid pace as a potential energy harvesting material. Within a short time span it has achieved the power conversion efficiency comparable to the similar mature technologies (crystalline Silicon, CIGS, CdTe etc.) available in the market. Unfortunately, PSCs have stability issues in real time operating conditions and posed a hurdle towards its commercialization. Various modifications and engineering aspects have been applied so far to cope up with this issue and among these players, ionic liquids (ILs) have certainly grabbed the attention of the researchers recently. ILs have unique and versatile properties like high ionic conductivity, thermal and electrochemical stability; which are suitable for application in PSCs. This review describes the fundamental, present status and future prospects of role of ILs in perovskite solar cells focussing on the stability and efficiency. Strategies regarding surface/interface modifications, engineering of interfaces and interaction of ions (cations/anions) from ILs with various perovskite precursors are discussed.